Lund, Ivar; Lazado, Carlo C. and Jokumsen, Alfred (2018) Manipulation of dietary fatty acids and effects on rainbow trout fry performance. [Effekt af manipulering af fedtsyre indhold i foder til regnbueørred yngel.] .
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Summary in the original language of the document
The Organic Regulation of fish farming states strong limitations on the sourcing of protein and fat (oil) ingredients in organic feed, i.e. aiming to phase out fishmeal (FM) and fish oil (FO) obtained from wild fish stocks and this may lead to a higher inclusion of other ingredients, especially of vegetable origin including proteins i.e. soybean; wheat; corn; barley; cottonseed; canola and peas, and oils i.e.: soybean; canola; linseed; sunflower; palm oil a.o. (Gatlin et al., 2007). A complete substitution of (FM) by vegetable protein alternatives may, however, lead to reduced performance in salmonids. Nutritional deficiencies and lack of essential amino acids; high dietary levels of antinutrients/ carbohydrates are typical factors leading to lower feed intake; lower digestibility,- feed utilization and growth and may have additional consequences for survival and robustness.
Several studies have shown that a total substitution of FO by individual or mixtures of vegetable oils do have same negatively effect on growth or feed efficiency provided that essential n-3 (Ω-3) and n-6 (Ω-6) long chain polyunsaturated fatty acids (LC-PUFA) requirements are met by the lipids contained in fish meal (Bell et al., 2003; Richard et al., 2006). Diets free of both FM and FO will contain no LC-PUFAs known to have specific important physiological functions. The three main important LC PUFAs are arachidonic acid (20:4 ARA Ω-6), eicosapentaenoic acid (20:5 EPA n-3) and docosahexaenoic acid (22:6 DHA n-3). While ARA is particularly important in reproduction, EPA and especially DHA are essential for neural development and as part of forming membranes and maintaining their fluidity (Sargent 1995). The addition of LC- PUFAs to vegetable based diets may improve performance and robustness of the fish and act as immune stimulants.
Several studies were performed with rainbow trout fry with supplementation of LC-PUFAs (EPA+ DHA in diets for which FM and /or FO had been partly or fully substituted with alternative ingredients of primarily vegetable origin. Survival growth performance, enzymatic activity; immune response and analytical FA composition were used to evaluate effects.
Summary translation
Det blev undersøgt hvorvidt foderets indhold af HUFA i foder til avlsfisk hhv. yngel påvirkede ynglens robusthed og performance. Tre grupper af avlsfisk blev fodret med tre forskellige typer forsøgsfoder med reduceret indhold af marine ingredienser (protein and olie) og erstattet med vegetabilske produkter. Forskellige mængder omega-3 fedtsyrer (EPA og DHA) blev tilsat de tre diæter. Efter ca. 6 måneders fodring blev æg fra de respektive moderfiske grupper befrugtet og flyttet til DTU Aqua klækkeri som øjenæg og klækkede kort efter. Analyser af total indhold af fedtsyrer og indhold af EPA og DHA i forsøgsdiæterne viste lineær stigning parallelt med inklusions niveauerne, som også afspejledes i analyserne af de tre grupper æg, dvs. en ”carry over effect af EPA og DHA” fra foder til æg. Tilsvarende var dog ikke tilfældet ved analyser af hannernes sæd. Resultaterne viste også, at erstatning af marint protein med vegetabilsk kan have negativ effekt på foder indtag, vækst og fordøjelighed og dødelighed hos regnbue ørred yngel. Endelig tydede resultater på, at regnbueørred er i stand til at danne HUFA ud fra kortere kædede fedtsyrer.
| EPrint Type: | Report |
|---|---|
| Keywords: | Rainbow trout, fry, fatty acids, HUFA, diet |
| Subjects: | Animal husbandry > Feeding and growth Animal husbandry > Health and welfare |
| Research affiliation: | Denmark > Organic RDD 2 > RobustFish |
| Deposited By: | Jokumsen, Senior Advisory Scientist Alfred |
| ID Code: | 33386 |
| Deposited On: | 23 Aug 2018 09:56 |
| Last Modified: | 23 Aug 2018 09:56 |
| Document Language: | English |
| Status: | Unpublished |
| Refereed: | Not peer-reviewed |
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